Variable venturi carburetors

ABSTRACT

A variable venturi carburetor comprises respective vacuum sustaining and throttle plates, swingably disposed in respective input and output ends of said carburetor, said ends being connected by a through passageway mixture conduit. A nozzle tube conduit extends from said inlet end to discharge into said through passageway mixture conduit intermediate said vacuum sustaining and throttle plates. Fuel orifices are defined respectively in said nozzle tube conduit between a vacuum sustaining plate and said nozzle tube conduit discharge, and in said through passageway mixture conduit adjacent said throttle plate.

nited States Patent [191 Kincade 1 VARIABLE VENTURI CARBURETORS [76]Inventor: Claude Robert Kincade, 804

Montgomery St., West Monroe, La.

122] Filed: Mar. 8, 1971 [2]] Appl. No.: 121,638

261/41 D, DlG. 53,41 C, 44 A, 63, 52, D16. 56', 123/157; 137/484 Dec.11, 1973 2,127,444 8/1938 Emerson .1 261/D1G. 39 3,334,876 8/1967Shorrock 261/41 R 3,351,327 11/1967 Simonet et al 261/50 A 3,680,8468/1972 Bickhaus et al. 261/56 Primary ExaminerTim R. Miles Att0rneyJamesB. Lake, Jr.

[57] ABSTRACT A variable venturi carburetor comprises respective vacuumsustaining and throttle plates, swingably disposed in respective inputand output ends of said carburetor, said ends being connected by athrough passageway mixture conduit. A nozzle tube conduit extends fromsaid inlet end to discharge into said through passageway mixture conduitintermediate said vacuum sustaining and throttle plates. Fuel orificesare defined respectively in said nozzle tube conduit between a vacuumsustaining plate and said nozzle tube conduit discharge, and in saidthrough passageway mixture conduit adjacent said throttle plate.

[56] References Cited UNITED STATES PATENTS 1,857,889 5/1932 Sturm261/41 D l,9l8,974 7/l933 Kirby 26l/D1G. 53

2,06l,494 11/1936 Weber 261/50 A 2,271,1l3 1/1942 Bracke i 26l/4l D X2,45l,563 l0/l948 LaGuardla 261/44 R X 2,638,330 5/1953 Morgenroth26l/23.l

2 3 E 9 Ex, 4 2

Q v 5 Q 6 Q Q I b Pmmcnm 1 $178,041

sum 1 [If 2 FIG CLAUDE R K'INCADE INVENTOR PATENIEflnm 1 ms smrznrz FIG4 CLAUDE R K/NCADE I NVENTOR.

VARIABLE VENTURI CARBURETORS This invention generally relates to animproved variable venturi carburetor and more particularly toimprovements of a previously filed US. Pat. application (ser. No.872,044) by me on Oct. 29, 1969.

An object of the invention is to provide a carburetor for internalcombustion engines that is simple in construetion, well adapted for itsintended purposes and relatively inexpensive to manufacture.

Another object of this carburetor invention is to provide a carburetorwith the novel means wherein a more precisely controlled fuel-airmixture may be obtained to help meet strict emission standards.

Still another object of this carburetor is to provide a carburetor withthe means to deliver those precise fuelair mixture over a wideoperational speed range.

These together with other objectsand advantages which will becomesubsequently apparent, reside in the details of construction andoperation as more fully hereinafter described and claimed, referencebeing had to the accompanying drawings forming a part hereof wherein:

FIG. I shows a crossection of this device in one of its simplist forms;

FIG. 2 shows a similar partial crossection wherein a different shape ofvacuum sustaining plate is used in connection with a nozzle tube conduitdisposed in a different manner;

FIG. 3 shows a more complete view of vacuum plate and nozzle tubeconduit relationship as shown in FIG.

FIG. 4 shows a different arrangement of a nozzle conduit tube and vacuumsustaining plate;

In carrying out the invention and referring more specifically to FIG. 1there is provided a through passageway mixture conduit (l) withoppositely disposed input and output ends, said conduit having at leastone swingably disposed vacuum sustaining plate (3) on axis (9) to openand partially close the intake end of conduit (1), at least one nozzletube conduit opening into said mixture conduit (1) at a point on thedownstream side of vacuum plate (3) when said plate is at its mostclosed position within the mixture conduit (1), said nozzle tube conduitgenerally serves the purpose of a mixture conduit at lower operatingspeeds, and operates primarily as a fuel nozzle for the conduit (1) athigher operating speeds and larger air flow rates; said nozzle tubeconduit (5) may have one or more vacuum plates (4) swingably disposed onaxis (11) within its inlet end or other suitable place to regulateairflow through said nozzle conduit; also at least one throttle plate(2) is swingably disposed on axis (11) within the outlet end of conduit(1) to open and close said conduit and thereby meter the amount ofmixture that exits from said conduit (1).

In operation the throttle plate (2) may be used to control idle mixturesin the same way that is common practice in conventional carburetors.Also idle fuel orifices (8) might be disposed in the nozzle tube (5) andbe controlled by the corporative action of throttle plate (2) and vacuumplates (3) and (4). Naturally some form of fuel regulating device andcutoff valve would shut off and control fuel flow from the reservoir (7)to the main fuel orifice (6) during the idle, as well as at all thedifferent phases of operation of this carburetor.

As throttle plate (2) is opened further from the idle position to allowmore mixture flow to exit; plate (4) should open and allow more airflowthrough nozzle conduit (5). This increased airflow through said nozzletube conduit (5) will tend to cause a vacuum effect that will draw fuelfrom controlled orifice (6) to be mixed with said airflow. Of coursesome form of linkage on the outside of the carburetor should be providedto interconnect the throttle plate (2) and vacuum sustaining plates (3)and (4). As the throttle plate (2) is opened towards its most openposition; vacuum plate (3) opens an appropriate corresponding amount toallow more air to be mixed with the controlled fuel air mixture exitingfrom nozzle tube conduit (5). At this point tube (5) might be consideredto be more of a fuel orifice that discharges fuel air mixtures to bemixed with air passing through conduit (1).

The important fact about nozzle tube conduit (5) is that at idle and lowspeeds it serves as a mixture conduit when said plate (3) is closed andat higher air-flow rates when plates (3) and (4) (if said plate (4) isused to control idle mixture) are opened to some degree, said tube (5)serves primarily as a fuel nozzle that feeds fuel into the airstreampassing through the conduit (1).

Another fact to be remembered about this or a similar arrangement ofplates and nozzle tube conduits is that the means are provided tosustain high airflow speeds, no matter what amount of airflow passesthrough conduit (1). This tends to atomize fuel more completely and inconjunction with appropriate fuel metering devices which might bedisposed in reservoir (7) to control the amount of fuel that exits fromorifices-(6) and (8), the means are present for a more precise mixturecontrol over all operating speeds.

Also it should be noted again that throttle plate (2) could be used asin FIG. 2 to control idle orifices that could be disposed about itsedges as in a conventional carburetor.

This would leave plate (4) to serve as a choke valve for nozzle tubeconduit (5) or it could be used to regulate an auxiliary fuel orificedisposed in said tube or not used at all, depending on the total design.

It is apparent that the flexibility this design allows by thedisposition of the nozzle tube (5) outlet opening with respect to theplacement of throttle plate ('2) and vacuum plates (3) and (4).

FIG. 2 shows another arrangement and shape of the nozzle tube conduit(5) and the vacuum sustaining plate (3). In this partial crossection thenozzle tube conduit (5) is mounted more or less in the center of theinlet end of conduit (1). a p

The original idea and concept is still retainedbecause the outlet end ofsaid tube (5) still terminates on the downstream side of the plate (3)when said plate is at its most "closed position within the conduit (1).

In this arrangement a pivoting pin (9) goes through nozzle tube (5) tofacilitate an axis fo said plate to open and close upon, wherein nonozzle pierced the plate (3) in FIG. 1. Again it is apparent that anynumber of combinations of nozzle tube conduits (5) and vacuum sustainingplates (3) may be envisioned. It is apparent that when plate (3) in FIG.2 is at its most closed position as shown that most air flow will bediverted through nozzle tube conduit (5). The idle orifices (8) areplaced about throttle plate (2) in this figure much as they would be ina conventional carburetor. No choke plate (4) is shown in FIG. 2although it is possible that one can be used if the total design sodictated.

FIG. 3 serves to further clarify the arrangement of vacuum plate (3) inrelation to nozzle tube conduit and its pivot pin (9).

FIG. 4 shows another arrangement of plate (3) tube (5) and pivot pin (9)that might be envisioned.

The interfunction of plates (2); (3) and (4) (when used) is a basic andimportant consideration and in conjunction with a suitable regulating,connecting linkage will provide the means for sustaining an adequateamount of vacuum about the outlet end of nozzle tube (5) to meter andatomize fuel from orifice (6) or other similarly placed orifices in amore precise manner.

Referring again to FIG. 1 it is envisioned that when throttle plate (2)is opened enough to pass a given amount of fuel air mixture to supply anengines normal medium speed requirements and when; by design the nozzletube conduit (5) is not being of sufficient size to efficiently passthis demanded amount of mixture; the vacuum plate (3) will be openedenough by an outside regulating mechanism to admit the extra amount ofair that the engine will need at said medium speed. Also a signal willbe sent by an outside interconnection mechanism to a regulatingmechanism in reservoir (7) to allow extra fuel to be discharged fromfuel orifice (6) down through tube (5) to be added to the increasedamount of airflow passing through conduit (1).

The foregoing illustrates the inter-relating action of various parts andmechanisms of this carburetor at a given speed. There is an infinitenumber of variations of plate openings just as there are an infinitenumber of given engine speeds.

The foregoing is also considered illustrative only of the principles ofthe invention. Further since numerous modifications and changes readilyoccur to those skilled in the art, it is not desired to limit the exactconstruction and operation shown and described, and accordingly, allsuitable modifications and equivilants may be resorted to, fallingwithin the scope of the invention as claimed.

What is claimed:

1. A variable venturi carburetor having oppositely disposed inet andoutlet ends and a fuel reservoir, and comprising: a through passagewaymixture conduit means defined in said carburetor between saidcarburetors inlet and outlet ends for providing a place to vaporize fueland mix it with air; a nozzle tube conduit defined in said carburetorand adapted to discharge into said through passageway mixture conduitmeans intermediate said carburetors inlet and outlet ends; a vacuumsustaining plate swingably mounted to open and partially close saidinlet end for controlling admission of air and for generating venturieffects in said through passageway mixture conduit means that arevariable with the swingable positions of said vacuum sustaining plate,said vacuum sustaining plate having a pair of flat plates transverselyspaced apart by reversely channeled plates, all said plates incombination defining a center hole adapted to receive said nozzle tubeconduit, and the reversely channeled plates being adapted to nest withsaid nozzle tube conduit when swung for their respective channels to beconcentric therewith; throttle plate means swingably mounted to open andpartially close said outlet end of said carburetor for controllingamount of output therefrom; and fuel orifice means defined in saidnozzle tube conduit and in said through passageway mixture conduit meansconnected to said fuel reservoir and discharging between said vacuumsustaining plate means and said outlet end for providing fuel in amountsdependent on flow of air in said conduits as per said generated venturieffects.

1. A variable venturi carburetor having oppositely disposed inet andoutlet ends and a fuel reservoir, and comprising: a through passagewaymixture conduit means defined in said carburetor between saidcarburetor''s inlet and outlet ends for providing a place to vaporizefuel and mix it with air; a nozzle tube conduit defined in saidcarburetor and adapted to discharge into said through passageway mixtureconduit means intermediate said carburetor''s inlet and outlet ends; avacuum sustaining plate swingably mounted to open and partially closesaid inlet end for controlling admission of air and for generatingventuri effects in said through passageway mixture conduit means thatare variable with the swingable positions of said vacuum sustainingplate, said vacuum sustaining plate having a pair of flat platestransversely spaced apart by reversely channeled plates, all said platesin combination defining a center hole adapted to receive said nozzletube conduit, and the reversely channeled plates being adapted to nestwith said nozzle tube conduit when swung for their respective channelsto be concentric therewith; throttle plate means swingably mounted toopen and partially close said outlet end of said carburetor forcontrolling amount of output therefrom; and fuel orifice means definedin said nozzle tube conduit and in said through passageway mixtureconduit means connected to said fuel reservoir and discharging betweensaid vacuum sustaining plate means and said outlet end for providingfuel in amounts dependent on flow of air in said conduits as per saidgenerated venturi effects.